Printing device

ABSTRACT

A belt type printer in which the conventional inking ribbon is replaced by a roller which is uniquely supported and arranged to insure the application of the correct amount of ink to the type characters at all times. A support member is carried by one of the pulleys of the printer to maintain the type characters in their correct positions relative to the roller, and the roller&#39;&#39;s location relative to the type characters is adjustable in three different modes. The printer also includes a novel guide member which is effective to hold the paper against the platen as the type characters leave the inking roller and approach the printing position and to prevent any misaligned characters from inadvertently touching the paper or the exposed surface of the platen during their approach.

[11] 3,826,191 [451 July 30, 1974 United States Patent [191 Pittis et ai.

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8 Claim, 8 Drawing Figures PRINTING DEVICE BACKGROUND OF THE INVENTION This invention relates to printing devices and more particularly to impact printers in which the individual type characters are supported by a movable belt.

The present invention, while of general application, is particularly well suited for use with automatic high speed data transmission systems. In order to accommodate the high input rate of the incoming data, the printers of such systems commonly support the individual type characters on fingers carried by a continuously moving belt. A series of hammers are positioned at the printing location opposite the paper-carrying platen of the device, and the hammers are selectively actuated as the appropriate fingers move past to print on the fly, so

to speak, and form an inked impression of the character on the paper. The ink is obtained from a movable ribbon interposed between the characters and the paper.

Heretofore, difficulties were encountered in the construction and operation of printing devices of the foregoing type. As an illustration, the inking systems of such prior devices proved deficient in a number of respects, including undue wear of the ribbons and the need for comparatively complex ribbon advance and reversing mechanisms. In addition, the amount of ink applied to the individual type characters has been subject to fairly wide variation, with the result that the printed text from the device was often uneven and in some cases difficult to read. A further problem encountered in many prior printing devices resulted from the tendency of the paper or other record medium to become bowed or otherwise spaced from the platen during its advance. This latter problem has been of special moment when the devices were operated at high speed, and the type characters occasionally became caught on the bowed edge of the paper as they moved toward the printing position.

SUMMARY Another object of the invention is to provide a printing device of the character indicated in which the ink applying means is readily adjustable to insure the application of the correct amount of ink to the type characters at all times.

A further object of this invention is to provide an impact printer in which the possibility of the individual type characters becoming caught on the record medium is substantially reduced.

Still another object of the invention is to provide ari impact printer in which the exposed surface of the platen is shielded from unaligned type characters as they approach the record medium.

A still further object of the invention is to provide a printing device utilizing comparatively simple mechanical components which is economical to manufacture and thoroughly reliable in operation.

In one illustrative embodiment of the invention, the printing device includes a continuous flexible belt which is supported for movement along a closed path between a drive pulley and a driven or idler pulley. A series of characterbearing type fingers is carried by the belt such that, as the belt is advanced along its path, the fingers move past a group of hammers at the printing location'and are selectively struck toward the papersupporting platen of the device. An inking roller is mounted adjacent the idler pulley in position to engage each of the type fingers and apply a uniform amount of ink to each finger. The position of the inking roller is readily adjustable such that each finger receives the correct amount of ink even after long periods of operation.

In accordancewith a particular feature of the invention, in several advantageous embodiments, a support member is carried by the idler pulley in spaced, coaxial relationship therewith. The support member is effective to hold and locate the type fingers against the inking roller as the fingers move around the pulley. The pressure exerted by the member on the fingers is uniform from finger to finger, with the result that a very precise amount of ink is applied to each finger.

In accordance with another feature of several important embodiments of the invention, a guide member is located adjacent the platen and is provided with an extension of unique configuration and arrangement. The extension holds the adjacent edge of the record medium against the surface of the platen, and it also shields the medium and the exposed platen surface as the fingers approach the printing location. With this arrangement, the possibility of the fingers catching or tearing the medium is substantially reduced, and any unaligned fingers are positively prevented from smearing the medium or the exposed surface of the platen with ink.

In accordance with still another feature of the invention, in some embodiments, the device includes novel positioning means for maintaining the inking roller in fixed but adjustable relationship with the path of the type-carrying fingers. This positioning means enables the making of three separate adjustments. The inking roller may be moved in an axial direction relative to the fingers, its axis may be tilted angularly with respect to the fingers, and it also may be moved in a lateral direction toward and away from the fingers. When the adjustment has been completed, a stop cam is moved into position to provide a preset adjustable stop position for the inking roller.

The present invention, as well as further objects and features thereof, will be understood more clearly and fully when read with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary perspective view of an impact printer in Vaccordance with an illustrative embodiment of the invention.

FIG. 2 is a fragmentary top plan view of the portion of the printer shown in FIG. l.

FIG. 3 is a partial sectional view taken along the line 3--3 in FIG. 2.

FIG. 4 is a partially cut away sectional view taken along the line 4-4 in FIG. 2.

FIG. 5 is a sectional view taken along the line 5 5 in FIG. 2.

FIG. 6 is an enlarged vertical sectional view of the inking roller and associated parts for the device.

FIG. 7 is a partially cut-away sectional view taken along the line 7-7 in FIG. 2.

FIG 8 is a schematic block diagram of a data transmission system for controlling the operation of the printer.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring to FIG. 1 of the drawings, there is shown an impact printer 10 which is of more or less conventional construction, but includes an inking apparatus 11 and a paper guide mechanism 12 in accordance with a preferred embodiment of the invention. The printer 10 produces inked impressions on a roll of paper 13 or other record medium. The paper 13 is supported and advanced in the usual way by a cylindrical platen 14 arranged in spaced juxtaposition with a continuously moving type carrier in the form of a flexible belt 15. This belt is adapted for movement in a counterclockwise direction, as viewed in FIG. 1, around a closed path between a drive pulley (not visible in FIG. 1) and a driven or idler pulley 16.

The belt 15 carries a series of flexible upstanding fingers 20. The upper end of each of the fingers includes a type face 21 bearing a letter or other character l to be printed. The direction of movement of the belt 15 relative to the record medium 13 is such that the type faces 21 traverse and print a line of characters on the medium as they move parallel to the axis of the platen 14 from the idler pulley 16 to the drive pulley.

A plurality of hammers 22 are disposed at a printing location indicated generally at 23. A separate hammer 22 is provided for each position at which a character may be printed. The hammers 22 are located within a closed path formed by the belt 15 and are controlled by corresponding electrically actuated solenoids 25. Upon the energization of a particular solenoid 25 by appropriate control circuitry, the corresponding hammer 22 pivots into contact with one of the fingers 20 to drive it against the surface of the record medium 13 and form a printed impression of the corresponding character. The hammer is then returned to its initial position by a spring 27.

As the fingers 20 move at a constant speed around the path defined by the belt 15 and past the printing location 23, they are selectively struck against the record medium 13 by the hammers 22. The ends of the fingers opposite the ends bearing the type faces 21 protrude beneath the belt 15. A light source 30 and a pair of photoelectric cells 31 are located on opposite sides of the protruding ends of the fingers such that the light from the source is interrupted as the fingers move past. Signals are thus produced which provide discrete indications of the location of each type face relative to the record medium. These signals are utilized in known manner to energize the selected solenoids 25 and actuate the hammers 22 at the appropriate times.

The foregoing description is but illustrative of a conventional combination of impact printer components. It will be apparent that to form printed impressions on the record medium 13 there must be an arrangement for supplying ink to the type faces 21 on the individual fingers 20. Particularly at high belt speeds, the amount of ink reaching each finger must be carefully controlled to insure legible and uniform impressions and to minimize unwanted ink spots on the record medium and the exposed surface of the platen.

For this purpose the printer 10 is provided with an inking roller 35. The roller 35 is spaced from the printing location 23 and is arranged with its axis parallel to that of the idler pulley 16 in position to engage each of the type faces 21 as they are carried around the pulley by the belt 15. The roller is impregnated with suitable printing ink and transfers an ink coating to each of the type faces shortly before the corresponding finger 20 leaves the pulley 16.

A generally disk-shaped support member 37 is disposed in coaxial relationship with the pulley 16. As best shown in FIG. 4, the support member 37 is spaced above the pulley 16 and is rigidly but removably affixed thereto by an integrally formed collar 38. In the illustrated embodiment the member 37 is made of aluminum, although in several advantageous arrangements the member is of plastic or other suitable material and is provided with a resilient O-ring around its periphery. The member 37 cooperates with the inking roller 35 and is disposed at the level of the type faces 21 on the fingers 20 such that the type faces pass between the member 37 and the roller. The member 37 engages the fingers 20 as they are carried around the puley 16 by the belt 15. With this arrangement, the member 37 provides support for each finger as it engages the roller 35.

The inking roller 35 is mounted on the upper end of an upstanding shaft 40, where the roller is held in place by a knurled nut 41. The shaft 40 is journaled in a tubular housing 42, and the lower end of the shaft is provided with a knurled collar 43. The housing 42 includes a threaded portion 44 adjacent its upper end. This threaded portion is slidably disposed in a corresponding aperture adjacent one end of a generally L-shaped slide plate 45. The housing 42 is held in fixed relationship relative to the slide plate 45 by two adjustment nuts 46 and 47 on opposite sides of the plate. By loosening the nuts 46 and 47, the housing 42 may be moved in an axial direction to similarly move the inking roller 35 relative to the fingers 20 and thereby vary the position at which the roller contacts the fingers. With this arrangement, as soon as the roller 35 begins to wear at a particular portion of its periphery, the roller may be moved either upwardly or downwardly such that it contacts the fingers at a different peripheral position. In addition, the roller may be readily inverted on the shaft 40 by removing the nut 41 to thereby expose a still further fresh surface to the fingers.

The slide plate 45 is adjustably mounted on an upstanding bracket 50. The bracket 50 includes a main body portion 51 which extends in a plane parallel to the axis of the pulley 16 and the inking roller 35 and is pivotally secured at its forward lower corner to a stand-off member on the adjacent side plate of the machine frame, as by a bolt 52 and a lock washer 53. Each of the two rearward comers of the portion 51 is provided with an elongated slot 54. Each slot 54 extends in a direction perpendicular to a radius drawn from the pivot bolt 52 and cooperates with a bolt 55 to limit the movement of the bracket 50 about the pivot bolt. Lock washers 56 for the bolts 55 serve to lock the bolts in place.

The bracket 50 is provided with a right angle portion 58 which forms a supporting ledge for the slide plate 45. The plate 45 includes longitudinally spaced slots 60 and 61 which accommodate respective bolts 62 and 63. These bolts carry lock washers 65 and suitable flat washers and lock nuts. The plate 45 is thus rigidly but adjustably attached to the bracket 50, such that upon pivotal movement of the bracket 50 about the bolt 52, the plate 45 moves with the bracket to vary the angular position of the axis of the inking roller 35 with respect to the character-bearing fingers 20. If the upper portions of the printed characters on the paper 13 are too dark or too light, for example, the position of the roller axis is adjusted to bring the periphery of the roller into parallel relationship with the type faces 21 and thereby insure uniform impressions. With the roller in its proper angular position, the bolts 52 and 55 are tightened to prevent further pivotal movement of the bracket 50.

The slots 641 and 61 and the corresponding bolts 62 and 63 permit limited sliding movement of the plate 45 with respect to the bracket portion 58 against the resistance of the lock washers 65. A rectangular opening 67 is provided in the plate 45 intermediate the slots 60 and 61. The opening 67 accommodates a generally cylindrical cam 70 which is pivotally mounted on the portion 58. To move the inking roller 35 in a lateral direction, toward and away from the type fingers 20, the slide plate 45 is pushed along the upper surface of the portion 58 until the roller reaches the desired position. This arrangement enables an adjustment of the degree of interference between the roller 35 and the fingers 20, such that a carefully controlled amount of ink is applied to each finger as it contacts the roller. The cam 70 is manually rotated with a screwdriver or similar tool so that it bears against the edge of the plate 45 within the opening 67 which is on the opposite side of the cam from the roller. When the roller 35 is in its proper position and the cam 70 is against the edge, the cam is locked in place by tightening the cap screw beneath the cam. The cam 70 serves to establish a stopping point to the movement of the plate toward the fingers, and it thereby enables the rapid resetting of the roller relative to the fingers without the need for re peating the adjustment.

As best shown in FIG. 7, the printer is provided with a guide plate 75 which forms a part of the paper guide mechanism 12. The plate 75 extends in a direction parallel to the rotational axis of the platen 14 and serves the usual function of guiding the paper 13 as it moves around the platen. An upstanding lateral extension 76v is provided on the plate 75 adjacent the inking roller 35. The extension 76 engages the paper 13 and holds the right hand edge thereof, as viewed in FIG. 7, in contact with the platen. In addition, the extension shields the exposed surface of the platen and the right margin of the paper from being smeared with ink by any unaligned fingers.

The drive pulley continuously rotates the flexible belt 15 around its closed path at a uniform speed. The belt 15 carries the individual type fingers 20 around the pulley 16 and into contact with the inking roller 35, where the type face 21 on each finger is held against the periphery of the roller by the support member 37 (FIG. 4) to apply a uniform quantity of ink to each type face. In some cases, particularly at high speeds, the paper 13 may exhibit a tendency to become slightly bowed as it is advanced by the platen 14, with the result that the right-hand edge of the paper billows into the path of the fingers as they approach the platen. Because of the extension 76 on the guide plate 75, however, this edge of the paper is maintained in contact with the platen, and the possibility of the fingers catching or tearing the paper is substantially eliminated. The fingers continue their movement to the printing location 23, and the printing hammers 22 are actuated to press selected tingers against the paper and thus form the desired inked impressions.

The print hammers 22 operate under the control of an electrical circuit shown schematically in FIG. 8. The circuit includes a remotely located transmitting unit 80 which sends out analog signals corresponding to the information to be printed. These signals are transmitted over` leased telephone lines or other suitable voice grade circuitry to a demodulator 82 at the printing location. The demodulator 82 converts the incoming analog signals into logic signals with the individual information bits in serial form. The bits which make up each character to be printed are arranged parallel to one another in a serial to parallel converter 84 and are then supplied to a decoder 86 which determines the identity of the particular characters.

The character signals from the decoder 86 are stored in a memory circuit 88. The circuit 88 holds each signal until the appropriate character finger 20 (FIG. 1) reaches the printing location 23. The signal is then released to energize one of the hammer solenoids 25, and the corresponding hammer strikes the back of the finger 20 as it moves past to form a printed impression of the character on the paper.

The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is 'recognized that various modifications are possible within the scope of the invention claimed.

l claim:

l. In an impact printer having plurality of type characters with printing faces mounted adjacent one another on independent flexible fingers carried by an endless belt which transports the faces around a closed path a predetermined distance away from one edge of the belt and means for inking each type face within a predetermined segment of said path, the improvement comprising means for applying a uniform amount of ink to each type face in which the inking means comprises an ink roller mounted along said path segment and which is rotatable about its central axis and there is cooperating with the roller a support member mounted adjacent said path segment, but spaced apart from said roller a predetermined distance, for supporting each finger as it travels through Vsaid segment, there being means for adjusting the position of the ink roller toward and away from the type faces passing along said path segment to control the amount of ink applied to each face while the finger carrying that face is supported by said member.

2. The improvement according to claim 1 wherein there are means for adjusting the ink rollers position along its central axis to cause a fresh portion of the roller to engage the type faces as desired.

3. The improvement according to claim 2 wherein there are means for adjusting the ink rollers position about a pivotal axis in the printer to enable the rollers periphery to be brought into parallel relationship with the faces of each type character as they engage the roller to ensure uniform transferral of ink to thereto.

4. The improvement according to claim 3 wherein the means for adjusting the position of the ink roller toward and away from the path segment includes slotted bracket device carrying the roller and a preset adjustable stop cam device for rapid resetting of the bracket to a desired position in which the ink roller will engage the type faces with a predetermined amount of pressure.

5. In a printing device having the improvement according to claim l and wherein the device also includes platen means in spaced juxtaposition with a portion of the closed path of the type faces for supporting a recording mediumand a guide member including a main body portion for guiding the record medium with respect to the platen, the additional improvement comprising: an extension to said body portion positioned between the platen and the ink roller in a location to shield the platen and the recording medium against being smeared with ink from inked type faces out of alignment with said path.

6. In a printing device having the improvement according to claim 2 and wherein the device also includes platen means in spaced juxtaposition with a portion of the closed path of the type faces for supporting a recording medium and a guide member including a main body portion for guiding the record medium with respect to the platen, the additional improvement cornprising: an extension to said body portion positioned between the platen and the ink roller in a location to shield the platen and the recording medium against being smeared with ink from inked type faces out of alignment with said path.

7. In a printing device having the improvement according to claim 3 and wherein the device also includes platen means in spaced juxtaposition with a portion of the closed path of the type faces for supporting a recording medium and a guide member including a main body portion for guiding the record medium with respect to the platen, the additional improvement comprising: an extension to said body portion positioned between the platen and the ink roller in a location to shield the platen and the recording medium against being smeared with ink from inked type faces out of alignment with said path.

8. In a printing device having the improvement according to claim 4 and wherein the device also includes platen means in spaced juxtaposition with a portion of the closed pathof the type faces for supporting a recording medium and a guide member including a main body portion for guiding the record medium with respect to the platen, the additional improvement comprising: an extension to said body portion positioned between the platen and the ink roller in a location to shield the platen and the recording medium against being smeared with ink from inked type faces out of alignment with said path.

* Il l 

1. In an impact printer having plurality of type characters with printing faces mounted adjacent one another on independent flexible fingers carried by an endless belt which transports the faces around a closed path a predetermined distance away from one edge of the belt and means for inking each type face within a predetermined segment of said path, the improvement comprising means for applying a uniform amount of ink to each type face in which the inking means comprises an ink roller mounted along said path segment and which is rotatable about its central axis and there is cooperating with the roller a support member mounted adjacent said path segment, but spaced apart from said roller a predetermined distance, for supporting each finger as it travels through said segment, there being means for adjusting the position of the ink roller toward and away from the type faces passing along said path segment to control the amount of ink applied to each face while the finger carrying that face is supported by said member.
 2. The improvement according to claim 1 wherein there are means for adjusting the ink roller''s position along its central axis to cause a fresh portion of the roller to engage the type faces as desired.
 3. The improvement according to claim 2 wherein there are means for adjusting the ink roller''s position about a pivotal axis in the printer to enable the roller''s periphery to be brought into parallel relationship with the faces of each type character as they engage the roller to ensure uniform transferral of ink to thereto.
 4. The improvement according to claim 3 wherein the means for adjusting the position of the ink roller toward and away from the path segment includes slotted bracket device carrying the roller and a preset adjustable stop cam device for rapid resetting of the bracket to a desired position in which the ink roller will engage the type faces with a predetermined amount of pressure.
 5. In a printing device having the improvement according to claim 1 and wherein the device also includes platen means in spaced juxtaposition with a portion of the closed path of the type faces for supporting a recording medium and a guide member including a main body portion for guiding the record medium with respect to the platen, the additional improvement comprising: an extension to said body portion positioned between the platen and the ink roller in a location to shield the platen and the recording medium against being smeared with ink from inked type faces out of alignment with said path.
 6. In a printing device having the improvement according to claim 2 and wherein the device also includes platen means in spaced juxtaposition with a portion of the closed path of the type faces for supporting a recording medium and a guide member including a main body portion for guiding the record medium with respect to the platen, the additional improvement comprising: an extension to said body portion positioned between the platen and the ink roller in a location to shield the platen and the recording medium against being smeared with ink from inked type faces out of alignment with said path.
 7. In a printing device having the improvement according to claim 3 and wherein the device also includes platen means in spaced juxtaposition with a portion of the closed path of the type faces for supporting a recording medium and a guide member including a main body portion for guiding the record medium with respect to the platen, the additional improvement comprising: an extension to said body portion positioned between the platen and the ink roller in a location to shield the platen and the recording medium against being smeared with ink from inked type faces out of alignment with said path.
 8. In a printing device having the improvement according to claim 4 and wherein the device also includes platen means in spaced juxtaposition with a portion of the closed Path of the type faces for supporting a recording medium and a guide member including a main body portion for guiding the record medium with respect to the platen, the additional improvement comprising: an extension to said body portion positioned between the platen and the ink roller in a location to shield the platen and the recording medium against being smeared with ink from inked type faces out of alignment with said path. 